Plastics overview: Polymers

A quick overview is required here. In the United States, the word plastic means "to mold" or "capable of being molded." We also use the word plastic to describe polymers. There are three main classes of polymers: thermosets, thermoplastics, and elastomers. In the knife world, we mainly use thermosets. These are polymers that are hardened into a permanent shape in the manufacturing process, and are often cured from a monomer-polymer mixture into a long-chain molecular links. Once hardened, the thermoset polymers can not be restored to their original components.

Though there are dozens of types of plastics, and hundreds of variations on those types and thousands of trade names for the varieties, I'll try to keep it simple, in modern knife handle terms. The specific thermosets most commonly used in knife handle construction by handmade knife makers are epoxies, phenolics, and polyesters. I'll go into greater detail in my upcoming book. This page also lists some thermoplastics that I've used in knife handle construction.

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Delrin (Acetyl Resin, Acetyl Plastic)

Delrin is a thermoplastic created by DuPont as a metal substitute. It is a friction reducing, tough, lightweight, wear-resistant plastic, and is approved for use in the food handling industry. I've used it before for chef's knives, where high temperatures, water resistance, and sterility are an issue. It is very tough, and has replaced other more brittle cellulose based plastics, and is used to make many things, including guitar picks. It's great for dive knives, as it cannot absorb gasses under pressures. The issue is bonding. Delrin has to be chemically etched before being bonded by epoxies or cyanoacrylates, but adhesive bonding with mechanical fasters can be effective. It is available in white, natural, and black.

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Micarta® (Phenolics)

Micarta® is a registered trade name, and not all phenolics are Micarta. The phenolics I use on my knives originate from Norplex-Micarta®, so carry the name Micarta.

Phenolics are the mainstay for the custom knife manmade or synthetic handle material industry. Micarta® is a phenolic thermoset plastic originally developed as an electrical insulator. It is a great material, and is often called by knife makers the Cadillac of Plastics. Phenolics are moderately hard, though metals and abrasive compounds will scratch them. They are very tough (resistant to breakage). They do not bend easily. They can be injected into many fibrous materials, like woods, linen, fiberglass cloth, canvas, paper and just about any fiber and I imagine that you could make a phenolic with dead bugs as a substrate if you wanted (hey, neat marketing idea!). The fibers reinforce the phenolic, making it even tougher and more resistant to breakage, though in knife handles, particularly if supported by the metal tang of the knife handle, this is probably overkill. So the fibers, arrangement, and color are chosen mostly for two other reasons: appearance and texture.

I've read frequently here on the internet that Micarta phenolics scratch easily. Evidently this misconception, once posted, was simply copied and pasted over and over until people actually started to believe it. Micarta phenolic is relatively hard and scratch resistant. It is harder than most woods, and is absolutely harder than ivory, bone, horn  or antler. When doing a scratch test, you will find that the corner of a penny will not scratch Micarta, but a hardened steel pin, steel bolt, or steel knife blade will scratch it. The same hardened steel blade will also scratch G10 and Carbon Fiber Reinforced Polymers. When you see the phrase that Micarta easily scratches, this is a misconception and error. By the way, how often does a knife handle contact hardened steel edges and why? Another Internet fallacy.

My most commonly used Micarta phenolic is black canvas, and when bead blasted, takes on a gray appearance, going well with bead blasted stainless steel blades. Here are some examples:

You can see that when bead blasted, micarta takes on a lighter tone. Here are some other colors and textures I commonly use:

There are obvious appearance properties of color choice, like a blue or red paper line in an ivory mass of Micarta® phenolic that looks neat. Camouflage colors or bright colors also have their appeal. Micarta phenolics come in just about any color, and here's a list of some that are available. The color is followed by the name of the reinforcing material (paper, fiber, linen, etc.) Not all colors come in all sizes.

See Accompanying Phenolic Color Chart Below

Ivory (Bone) Paper	Antique Linear Paper	Black Paper	Red Linen
Green Canvas	Black Canvas	Natural Canvas	Orange/Black Paper
Turquoise Canvas	White Linen w/2 Red Lines	Turquoise/Black Canvas	White Linen
Black Paper w/Multicolored Lines	Red/Black Linen	Black Linen
Green Linen	Natural Linen	Black Paper w/White, Red Lines
Maroon Linen	Chocolate Paper	Green/Black Linen

Though there are a whole rainbow of colors available, you won't see many on my site used in custom knives. My clients simply do not request odd colors that often. The most popular choice is black canvas, which is then bead blasted for a rough, gray color, and some tooth that can aid in gripping the knife in slimy environments, the most often being seawater (not blood). Micarta phenolics that have been bead blasted will darken with the oils of human hands, but can be restored by a cleaning with denatured alcohol, lacquer thinner (use carefully and sparingly) or even brake cleaner aerosol spray. A denser appearance with more vibrant color can be achieved after cleaning with a light coating of WD-40, wiped off.

Micarta® phenolics are waterproof, somewhat resistant to heat, a pretty much "zero care" plastic.

Please note: Micarta phenolics are usually used on my tactical knives, and not used on knives with elaborate construction, destined for collector's grade finishing and accoutrements. Knives of this higher caliber usually include gemstone handles and exotic skin inlaid leather sheaths.

See Accompanying Color Chart Below

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G-10 Composite

G-10 is a recent addition to the synthetic or man-made handle material group. G-10 is a glass (fiberglass) reinforced epoxy, and it is a very tough, hard, and durable handle material. Because it has fiberglass linen as reinforcement, it is physically stronger (more break resistant) than Micarta phenolic. It is scientifically manufactured, and the epoxy used is a specialized industrial grade which has heat resistance properties. It's also made with electrical grade, non-alkali glass cloth, and formed and catalyzed under heat and pressure.  It's waterproof, a little harder and slightly more brittle than Micarta, and has a more profound pattern when ground and finished, which is probably its greatest appeal.

If you look around the web, you'll see guys trying to make G-10 or phenolics by hand. I've seen denim pants, with five minute discount store epoxy mixed together, I've seen jigs to try to press it all together. This may be a fun craft pursuit, but it is a poor substitute for professionally made materials like real G-10, Micarta® phenolic and Carbon Fiber. The industrial stuff is hard, tough, solid with no voids, and very durable.

Like phenolics, G-10 that has been bead blasted will darken with the oils of human hands, but can be restored by a cleaning with denatured alcohol, lacquer thinner (use carefully and sparingly) or even brake cleaner aerosol spray. A denser appearance with more vibrant color can be achieved after cleaning with a light coating of WD-40, wiped off.

G-10 comes in many colors:

Black	Blue	Blue and Black	Green, Black and Pistachio
Green	Pink	Hunter Orange	Midnight Tiger- Tan, Black
Yellow	Red	Lager Ale- Amber	Tiger- Orange and Black
Red and Blue	Tan	Red and Black	Natural- Light Green

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See Accompanying Color Chart Below

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Carbon Fiber Reinforced Polymers

Carbon fiber is a blanket term given to a structure of typically woven strands of carbon in a polymer or thermoset plastic (epoxy). This material's actual name is carbon fiber reinforced polymer. Since it is molecularly close to graphite, the term graphite composite or just graphite is often used in objects built of carbon fiber reinforced polymers.

The advantages of carbon fiber when used for knife handles are usually only one: the appearance. Carbon fiber when finished creates a noticeable woven, braided appearance in the surface, an appearance some would call "techie" or even machine-like. Some call it futuristic and sophisticated, but remember, with this material it is all about the appearance. Carbon fiber reinforced polymers are brittle when compared to G10. This means on a knife handle, it's best served if well protected at the borders and edges to prevent damage. Not a material expected to be used on a tough duty knife like a combat weapon or survival tool, but more frequently chosen for a certain look on a collector's piece.

Another issue with carbon fiber reinforced polymers is expense. This is very pricey stuff. It's abrasive to machine, costlier to produce and comes in only a few colors. But when you want that certain look, it can deliver.

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Color chart for Micarta® (phenolic) and G-10. (Thanks to Sheffield Knifemaking Supply)

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Homemade "Micarta" (epoxy)

You'll see some handle material called "handmade micarta" or "homemade micarta." This is not Micarta®. Micarta® phenolic is a professionally manufactured phenol-formaldehyde plastic. What these guys are calling Micarta is actually epoxy, a totally different thermoset, based on epichlorhydrin/bisphenol-A reaction.

Homemade epoxy products are usually made from quick setting epoxy adhesives, coated on fibrous textiles (canvas, denim, and rope have been used) and left to cure. Using the word "Micarta" should not be done when referring to these materials. Phenolics are much harder, tougher, and much more resistant to heat than epoxy. Phenolics are structurally strong, of uniform density, as they are cured under heat and pressure. Epoxies are not. Phenolics will not soften with heat, cheap epoxies will.

Please understand I'm not talking about the industrial epoxies used to create G10 and Carbon Fiber Reinforced Polymers. I'm talking about the over-the-counter hardware store epoxies. You'll see on this page that G-10 is a glass (fiberglass) reinforced epoxy, and it is a tough, hard, and durable handle material also, and will not soften with heat. Remember that the methods used to manufacture G -10 are industrial, and the epoxy used is a specialized industrial grade which has heat resistance properties. It's also made with electrical grade, non-alkali glass cloth, and manufactured under heat and pressure.

Don't get me wrong; I love my epoxies, when used for their proper adhesive purpose. But to form a handle from five minute epoxy and someone's old pants is not what you would expect to find on fine custom knives. In making these epoxy-based handles, there is no way to effectively remove air pockets, voids, and contamination as industrial process control is out of the reach of individual knife makers.

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Phenolic Impregnated Woods: Dymondwood

Sold under the brand names Pakkawood®, Staminawood®, and Dymondwood®, and Colorwood®, these are actually plywood products,  constructed from birch. Today, these products are made and sold by Rutland Plywood Corporation, who bought out Pakkawood years ago, and modified and updated their technology. The name Pakkawood is discontinued, and the name Staminawood is another name for the same product. There are other names, but today, in knives, it's all Dymondwood.

How it's made: Dymondwood is a densified, impregnated, hardwood composite with the mechanical properties of high density hardwoods, acrylics, polycarbonates, and even brass. Dyes are vacuum impregnated into the wood, then the wood is pressure-impregnated with phenolic resin at very high pressures, then highly compressed into plywood blocks at 29 plies per inch. With the high compression rates and solid massing of the material, this creates a very dense, solid wood product, that is pretty much waterproof. They can be a bit brittle when used in thin cross sections, though hold up extremely well on knife handles. They're warp free and stable. Though I don't use these often (some of the colors are quite garish), some clients request them and I'm happy to accommodate them. These stabilized laminates are very durable, polish brightly, and are long lived, some of the only waterproof wood products available. Great for clients who wish for a wood look, but require high moisture and exposure resistance typical in combat arms, tactical knives, kitchen knives, and hunting and specialty knives. Color charts and descriptions are below. Download the brochure of current Dymondwood products from Rutland at this link.

Dymondwood Colors

Dymondwood by Rutland Plywood Corporation publishes a brochure on Dymondwood. Here are the color groups from that brochure, and the names listed in the table on the left. Please click on the thumbnail photos for a larger view.

Nylon

Nylons are a group of thermoforming synthetic polymers. Nylon can sometimes outperform metals in applications like gears and rub plates, where high abrasion must be considered. Nylon 6/6 is the strongest over the widest range of temperatures, and has the highest melting point. Nylon has very high impact resistance, is very stable at a wide range of temperatures, and has good chemical resistance. A special use knife handle material, Nylon is available mostly in black, white, and natural. Though I've rarely used nylon for knife handle materials, I have used it in stands and displays as a strong, neutral component.

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Pyralin and Cellulose: Alternative Mother of Pearl: (mother of toilet seat!)

Pyralin is one of the names for a manmade material that is used to imitate mother of pearl, or nacre. It is essentially celluloid. Celluloid evolved from nitrocellulose and DuPont and the explosives industry in the early part of the 20th century. Naming cellulose Pyralin was an attempt to portray it as a more natural, not manmade material. DuPont pushed Pyralin in their use for "modern, stylized toilet ware" in the early 1930s, so many toilet seats were made of this material. After all, it looked pearly and expensive, and who wouldn't want to be reminded of the ocean while they're in the bathroom? Craftspeople would later cut up the toilet ware and use for musical instrument inlays, knife handles, and artwork to imitate the limited and expensive real mother of pearl. It is still used in some forms today for knife handles, mainly to imitate natural materials, and sometimes to create visual interest with garish colors and patterns.

I do not, nor will I ever use the stuff! No good maker in his right mind would; it is a tacky material typically found on foreign or poorly made knives. I just thought you might like to know the history.

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Alternative Ivory

Called Alternative Ivory, some this material is cast polyester. Though it may be an alternative to expensive or prohibited ivory, this is simply ivory-colored plastic. Polyester does not even approach the durability of phenolics or G-10. Another alternative ivory is based on dyed epoxy. I don't use it, and wouldn't expect to see it on finely made knives.

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Corian®

Corian® is a registered trade name for an acrylic thermoplastic with alumina trihydrate. Since it is a thermoplastic, it can be formed, bent, shaped, and deformed by the application of mere 300°F heat. It is not heat-resistant like Micarta® phenolic or G-10, but I've seen some knives handled in this material. It is not abrasion-resistant, and even the manufacturer recommends sealing the surface with coatings to prevent staining. I don't use it, and don't expect to see it on finely made custom or handmade knives. There are other trade names for similar products, like Meganite®, LG-HIMACS®, Staron®, Wilsonart Gibraltar®, and Livingstone®. There are even countertops based on polyester-based plastics rather than acrylics, which should be much tougher, harder, and heat resistant. Still, do they belong on knife handles or on your bathroom counter?

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